Hand-held power jigsaw

ABSTRACT

A hand-held jigsaw includes a saw blade and control element for automating a tracking the saw blade, the hand-held jigsaw, or both along layout lines. A sensor, preferably a camera unit, detects a layout line provided on a work piece.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is a divisional application of co-pending U.S.application Ser. No. 12/281,442, filed Sep. 2, 2008. The inventiondescribed and claimed hereinbelow is also described in German PatentApplication DE 10 2006 052 608.5 filed on Nov. 9, 2006. These GermanPatent Applications, whose subject matter is incorporated here byreference, provides the basis for a claim of priority of invention under35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The present invention is based on a hand-held jigsaw.

For example, the publications US 2005/0060896 A1 and US 2005/0257985 A1have disclosed jigsaws that are referred to as “scrolling jigsaws” andin which the saw blade is situated so that in addition to executing thestroke motion, it can be rotated manually independently of the sawingmotion. This additional function facilitates the sawing of sinuous cuts.

Without additional guidance-assisting elements, sawing precisely along apredetermined contour with a jigsaw requires a large amount of practice.This task is additionally complicated by the exertion of transverseforces that cause the saw blade to go astray. Providing laterallysupporting assistance systems or various navigation aids (e.g. lasers)reduces these problems, but does not eliminated them.

SUMMARY OF THE INVENTION

The invention is based on a hand-held jigsaw, in particular a scrollingjigsaw.

According to the invention, control means are provided that make itpossible to automate a tracking of a saw blade and/or of the hand-heldjigsaw along layout lines. In this context, a “control means” isunderstood in particular to be a means that permits a requiredorientation of the saw blade and/or the hand-held jigsaw and/or acomponent of the hand-held jigsaw such as a glide element to be detectedand/or adapted to the orientation. This control means can be a detectionunit such as a sensor system embodied in the form of a sensor and/or anactuator system embodied in the form of an actuating unit such as aservo motor and/or a step motor and/or a piezoelectric actuator.Alternatively, it would also be conceivable to use a DC motor. The term“tracking” here defines an orientation along a predetermined path thatis preferably indicated by means of a marking. This marking can be alayout line such as a previously drawn pencil line and/or anothermarking deemed suitable by a person skilled in the art, such as anindentation and/or some other form of profiling.

The system is used to assist an operator and therefore to facilitate thesawing procedure. Taking advantage of the existing degree of freedom ofthe saw blade in the form of the already implemented rotation axis, thehand-held jigsaw is equipped with a special sensor system for detectinga previously drawn line or layout line and a corresponding actuatorsystem for automatically adjusting the saw blade angle from an anglerange of a pivot angle. The rotation axis here is defined by a normalthat extends through a center point of a plane defined by a thicknessand a width of the saw blade. Alternatively, the rotation axis of thesaw blade can also be situated other than at its center point. In thiscase, the pivot angle represents the angle by which the saw blade can bemaximally adjusted around its longitudinal axis in relation to alongitudinal axis of the glide element and/or another guidance componentdeemed suitable by a person skilled in the art, e.g. a chassis. Thispivot angle is preferably an angle of between 0° and 90°. By contrast,the saw blade angle of the saw blade is the angle that is actually setbetween the lateral span of the saw blade and the longitudinal axis ofthe glide element or a guidance component. By means of a saw blademotion that is overlaid with a hand-guided movement of the operator, itis possible to more precisely track a previously drawn contour. Straightcuts can also be implemented without additional guides.

This produces a significantly improved work result while simultaneouslysimplifying operation.

It is also advantageous if it is possible to switch off means that areprovided for automating a tracking of the saw blade and/or the hand-heldjigsaw along layout lines. This makes it possible to create a hand-heldjigsaw that can be used in a particularly flexible fashion.

If a hand-held jigsaw has a pivotable saw blade that can be driven bythe control means, then a tracking of the previously drawn line by thesaw blade can occur in an advantageous, structurally simple fashion. Theterm “pivotable” here is particularly understood to mean a turningand/or rotation of the saw blade in an axis that preferably extendsparallel to a longitudinal span of the saw blade. In this connection,the turning can be achieved by clamping the saw blade into a tool socketand/or through some other exertion of force on the saw blade.

The invention is also based on a hand-held jigsaw, in particular ascrolling jigsaw.

According to the invention, a sensor is provided for detecting a layoutline provided on a workpiece. The term “sensor” is understood inparticular here to mean a camera unit and/or a contrast sensor unitand/or an eddy current sensor unit. This makes it possible to achieve adetection of a desired cutting direction in a particularly advantageous,inexpensive, structurally simple fashion.

Also according to the invention, optical mouse sensors are provided fordetermining a speed and/or a movement direction. The term “optical mousesensor” is understood here to mean a sensor that uses optical means suchas a light-emitting diode or laser diode to illuminate a supportingsurface, evaluates a light reflected against the supporting surface,calculates a speed based on the change of a physical surface of thesupporting surface, and from this, calculates the movement data in the xand/or y direction. Alternatively, the movement direction and/or theadvancing speed can also be determined by means of a running wheel withan angular displacement transducer, e.g. a rolling element withcorresponding photoelectric beam, detectors that detect a movement in atleast two directions such as an x direction and a y direction. Inaddition, means that are used to compare individual camera images canalso be provided to determine the advancing speed. The use of opticalmouse sensors makes it possible for a rugged sensor system fordetermining the speed and/or a movement direction to be produced in aparticularly simple and inexpensive fashion.

It is also advantageous if an actuator with a regulator is provided. An“actuator with a regulator” is understood here to be a unit thatprocesses data from a detection unit, particularly in a control loop,and/or reacts to and/or transmits generated control signals. This unitis preferably embodied in the form of a servo motor and/or a step motorand/or a piezoelectric actuator and/or a DC motor with a regulator unit.It is thus possible for a control loop for precisely tracking apredetermined cutting line to be implemented in a structurally simpleand inexpensive fashion.

According to the invention, a display element is produced, which isprovided to display a recommended advancing direction. A “displayelement” is understood here to mean an element that optically,acoustically, and/or tactilely informs the operator of the path detectedby a sensor or of a course of the layout line. The display element herecan be composed of LEDs and/or a display and/or another data unit deemedsuitable by a person skilled in the art. This makes it advantageouslypossible for an operator to receive information relating to a desiredmovement direction, regardless of whether the operator is able to seethe saw blade. This makes it possible for an operator to stay within anoptimal working region that represents an angular range of the possiblesaw blade angle.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages ensue from the following description of the drawings.An exemplary embodiment of the invention will be explained in greaterdetail in conjunction with the associated drawings. The drawings, thedescription, and the claims contain numerous defining characteristics incombination. Those skilled in the art will also suitably consider thedefining characteristics individually and unite them into othermeaningful combinations.

FIG. 1 shows a hand-held jigsaw according to the invention,

FIG. 2 shows a glide shoe of the hand-held jigsaw according to theinvention, embodied in the form of a base plate and equipped withoptical sensors,

FIG. 3 shows an alternative glide shoe of the hand-held jigsaw accordingto the invention, embodied in the form of a base plate,

FIG. 4 shows an alternative glide shoe of the hand-held jigsaw accordingto the invention, embodied in the form of a base plate and equipped withalternative sensors, and

FIG. 5 shows a top view of the hand-held jigsaw.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective side view of a hand-held jigsaw 9 according tothe invention, embodied in the form of a scrolling jigsaw. The hand-heldjigsaw 9 includes a machine housing 44, a main handle 46 integrated intothe machine housing 44, and a tool socket 48 containing a tool in theform of a rotatably supported saw blade 12. A glide element or glideshoe 8 in the form of a base plate is situated on a side 50 orientedtoward the work piece 18 to be machined. This glide shoe 8 permits thehand-held jigsaw 9 to advantageously glide on the work piece 18. On theside 52 oriented away from the saw blade 12, in a region that can beassociated with the main handle 46, a guide knob is provided, which isused for an at least manual guidance of the hand-held jigsaw 9. Themachine housing 44 also contains a motor that is not shown in detail. Onthe main handle 46, an actuation switch 56 is provided, which can beused to switch the hand-held jigsaw 9 on and off. In a side region 58 ofthe machine housing 44, an adjusting switch 60 is also provided, whichcan be used to adjust the glide shoe 8 in relation to a main span 62 ofthe saw blade 12.

The hand-held jigsaw 9 includes control means 10, 100 that enable anautomation of a tracking of the saw blade 12 along the layout line 14.The control means 10 is situated in a part 66 of the machine housing 44spaced apart from the main handle 46 in the axial direction 64. Thecontrol means 10 includes a sensor 16 for detecting or opticallyscanning a marking or layout line 14 in the form of a normal pencil line3 provided on the work piece 18. The sensor 16 is composed of a cameraunit 7 that preferably includes a low-cost camera and that is associatedwith a processor unit 28. In principle, the sensor 16 could also be acontrast sensor unit 20 and/or eddy current sensor unit 22 associatedwith a respective processor unit 28. For an optimal detection of thepreviously drawn line 14, it would also be conceivable for the eddycurrent sensor 22 to be situated in the glide shoe 8.

A monitoring region 68 of the sensor 16 and of the camera unit 7 extendstoward the work piece 18 in the same direction as the main span 62 ofthe saw blade 12 and covers a 360° angular range around the saw blade12. The monitoring region 68 of the camera unit 7 represents the regionin which the saw blade 12 functions in an operating mode, preferably asawing procedure of a work piece 18. Around the saw blade 12, the glideshoe 8 has a semicircular opening 70 in which the saw blade 12 iscentrally situated. In the direction of an advancing direction 38 and inthe direction of the monitoring region 68, the opening 70 has arectangular viewing window 102. The glide shoe 8 also has a referencemark 74 that represents the intersecting point of an edge 76 of theglide shoe 8 with a longitudinal axis 78 of the glide shoe 8 (see FIG.2).

FIG. 3 shows an alternative embodiment of the glide shoe 8. In thiscase, the central opening 70 widens out in a V-shape to form a viewingregion 72.

FIG. 4 shows another alternative embodiment of the glide shoe 8 with acircular opening 70. In this case, the glide shoe 8 is closed in themonitoring region 68 and is embodied as transparent, e.g. is composed ofPlexiglas, in order to make it possible to monitor the layout line 14 onthe work piece 18 (see FIG. 4).

In addition, the machine housing 44 of the handheld jigsaw 9 contains acompact actuator system 2 that is able to adjust the saw blade 12 arounda rotation axis 1 in an automated fashion. The control means 100 isprovided for this purpose. For the tracking of the rotatable saw blade12, the saw blade is driven in rotary fashion by the control means 100.The control means 100 represents an actuator unit 30, embodied in theform of an actuator with a regulator 34 in the form of a step motor bymeans of which it is possible to adjust a saw blade angle 26 of a sawblade 12. The control means 100 and the step motor can also be situatedin a space-saving fashion as an alternative to the guide knob 54. Inthis case, the saw blade angle 26 is an angle □ from the angular rangeof a pivot angle 80 that is actually set between the width span 82 ofthe saw blade 12 and the longitudinal axis 78 of the glide shoe 8. Thepivot angle 80 represents the angle □_(max) by which the saw blade 12can be moved around its longitudinal axis, which extends parallel to themain span direction 62 of the saw blade 12, in relation to alongitudinal axis 78 of the glide shoe 8 (see FIG. 2).

With the aid of the control means 10, 100, namely the sensor 16 and theactuator unit 30, it is possible to implement a control loop in order toachieve the most exact possible tracking of the predetermined line orlayout line 14. The exceptional feature in this case lies on the onehand in the fact that an analog image processing is used to detect thelayout line 14 and on the other hand, lies in the automation of thesystem. It is consequently possible to execute clean, precise cuts byhand and to actively prevent a deviation of the saw blade 12.

An operating sequence will be described in greater detail below.

The sensor 16 in the form of a camera unit 7 detects individual points 4of the previously drawn line or layout line 14. In this case, in orderto detect the layout line 14, the sensor 16 uses an analog imageprocessing that uses a division of the monitoring region 68 intoindividual search lines 6 without digital image processing. In theanalog image processing, the use of the camera unit 7 is particularlyadvantageous since it does not require calculation-intensive digitalimage processing.

The collected sensor information and the data associated with thedetected points 4 are then transmitted by the sensor 16 to the processorunit 28, which processes the detected points 4 further and based onthem, interpolates and adapts an actual path curve 24 (spline). Theprocessor unit 28 can be a microcontroller or another processing unitdeemed suitable by a person skilled in the art.

The processing unit 28 calculates and generates control signals andtransmits control signals to the actuator unit 30 for an adjustment ofthe saw blade angle 26. By means of an actuating element with aregulator 34 in the form of a step motor, the actuator unit 30 thencorrespondingly adapts the saw blade angle 26, i.e. the angle □ aroundthe longitudinal axis parallel to the main span direction 62 of the sawblade 12, as a function of the overlaid user guidance by means of theguide knob 54 of the hand-held jigsaw 9.

At the same time, the use of the sensor 16 and the camera unit 7 alsooffers the possibility of measuring additional reference marks 74 bymeans of the glide shoe 8. Furthermore, the sensor 16 can be used fordetecting the set saw blade angle 26 and for determining the rotationangle of the saw blade 12. This makes it possible to eliminateadditional cost-intensive sensors that unnecessarily take up space.

An additional, alternative embodiment is the integration of a detectionof an advancing speed. To this end, optical mouse sensors 5 are situatedin the glide shoe 8 on a side 84 oriented toward the work piece 18 anddetermine the speed and a movement direction, preferably in the x and/ory direction (see FIG. 3).

FIG. 4 shows another possibility for detecting the advancing speed. Inthis case, a simple running wheel with an angular displacementtransducer 32 is provided, e.g. a rolling element 86 with correspondingphotoelectric beam detectors 88. In principle, other approaches are alsoconceivable, for example the comparison of individual camera images bymeans of the processor unit 28. Within certain limits, the system canalso be implemented without a speed measurement.

When the hand-held jigsaw 9 is used, i.e. during a sawing process, anoperator guides the hand-held jigsaw 9 manually by means of the mainhandle 46 and guide knob 54; the operator must roughly predetermine thecutting direction. The system composed of the control means 10, 100,i.e. of the sensor 16 and actuator unit 30, is conceived only for thefine regulation that compensates for irregularities in the saw bladepath and/or user guidance.

This system is understood solely as an assisting system, i.e. if nolayout line 14 can be detected (end of a line, multiple lines), thesystem gives a warning by means of an acoustic and/or optical unit 90,stabilizes the current saw blade angle 26, and leaves the control up tothe operator, as in conventional jigsaws. No active intervention occurs.If so desired, the system, which can be associated with one or moremeans and which permits automation of a tracking of the saw blade 12and/or the hand-held jigsaw 9 along layout lines 14, can be switched offat any time, even preferably manually by the operator. The systemadvantageously includes the actuator system 2, at least one orspeed-detecting sensor such as the optical mouse sensor 5, the controlmeans 10 in the form of the sensor 16 and the camera unit 7, the controlmeans 100 in the form of the actuating unit 30, and the actuator with aregulator 34. For the switching off, a switch 92 is provided in theregion of the main handle 46 on the machine housing 40.

As shown in FIG. 4, a display element 36, e.g. in the form of LEDs 40and/or a display 42, is situated on a side 94 of the machine housing 44or main handle 46 oriented toward the operator, in the operator's fieldof view. This display element 36 is provided to display a recommendedadvancing direction 38, for example symbolized by means of an arrowsymbol 96 composed of light-emitting diodes or LEDs 40. The operator isthus shown the direction in which the saw movement must be corrected.Consequently, the display element 36 makes it possible for the operatorto stay within an optimum working region that represents an angularrange of the possible saw blade angle 26.

In another embodiment of the invention, in order to improve visibility,a blower 98 is provided, which is able to remove or suck away machiningresidue generated by the sawing process.

On the whole, this makes it possible to significantly simplify theguidance of the hand-held jigsaw 9 while achieving a simultaneouslyimproved sawing result. Another advantage of this system lies in thefact that the often poor visibility of the sawing location now playsonly a subordinate role since the fine guidance is performed by thesystem anyway.

1. A hand-held jigsaw, comprising: a saw blade; control means forautomating a tracking of an element selected from the group consistingof a saw blade, the hand-held jigsaw, and both along layout lines; and asensor for detecting a layout line provided on a work piece, wherein thesensor is configured to detect individual points of a previously drawnline.
 2. The hand-held jigsaw as recited in claim 1, wherein the sensoris a sensor selected from the group consisting of a contrast sensorunit, an eddy current sensor unit and both.
 3. The hand-held jigsaw asrecited in claim 2, wherein the contrast sensor unit or the eddy currentsensor unit is configured to interpolate an actual path curve based onthe detected points.
 4. The hand-held jigsaw as recited in claim 3,wherein the contrast sensor unit or the eddy current sensor isconfigured to adopt a saw blade angle as a function of an overlaid userguidance of the hand-held jigsaw.
 5. A hand-held jigsaw, comprising: asaw blade; control means for automating a tracking of an elementselected from the group consisting of a saw blade, the hand-held jigsaw,and both along layout lines; and a sensor for detecting a layout lineprovided on a work piece, wherein the sensor is a sensor selected fromthe group consisting of a contrast sensor unit, an eddy current sensorunit and both.
 6. The hand-held jigsaw as recited in claim 5, furthercomprising a processor unit that is configured to perform a processselected from the group consisting of generating control signals,transmitting control signals, and both to an actuator unit for anadjustment of a saw blade angle.
 7. The hand-held jigsaw as recited inclaim 6, wherein the actuator unit adapts the saw blade angle as afunction of an overlaid user guidance of a hand-held jigsaw.
 8. Thehand-held jigsaw as recited in claim 6, wherein the actuator unit is amechanical/actuator system for adjusting the saw blade angle of a sawblade.
 9. The hand-held jigsaw as recited in claim 5, further comprisingoptical mouse sensors for determining a speed and a movement direction.10. The hand-held jigsaw as recited in claim 5, further comprising meansfor comparing individual camera images to determine an advancing speed.11. The hand-held jigsaw as recited in claim 5, further comprising anactuator with a regulator.
 12. The hand-held jigsaw as recited in claim11, wherein the actuator with the regulator is a unit selected from thegroup consisting of a servo motor, a step motor, and a piezoelectricactuator, and any combination thereof.
 13. The hand-held jigsaw asrecited in claim 1, wherein means that permit an automation of theelement is switchable.
 14. The hand-held jigsaw as recited in claim 1,further comprising a display element provided to display a recommendedadvancing direction.
 15. The hand-held jigsaw as recited in claim 14,wherein the display element is selected from the group consisting ofLEDs, a display, and both.
 16. The hand-held jigsaw at least as recitedin claim 1, wherein the saw blade is pivotable and drivable by thecontrol means.
 17. The hand-held jigsaw as recited in claim 1 or 5,wherein the hand-held jigsaw is a scrolling jigsaw.